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1.
The compounds CaCo2Te3O8Cl2, SrCo2Te3O8Cl2 and SrNi2Te3O8Cl2 were synthesized via solid–gas reactions and investigated using single-crystal X-ray diffraction. While the compound CaCo2Te3O8Cl2 formed large enough single crystals to allow for a detailed structural analysis, crystals of the Sr-containing compounds yielded evidence that they are isostructural. CaCo2Te3O8Cl2 crystallizes in the monoclinic system, space group P21/c, a = 6.537(2) Å, b = 9.088(2) Å, c = 19.500(9) Å, β = 113.36(4)°, Z = 4. It exhibits [CoO5Cl] helical chains along the [010] direction, connected by [CaO8] polyhedra, [TeO3E] tetrahedra and [TeO4E] trigonal bipyramids (the lone pair of electrons on TeIV is designated as E) to form a layer. The layers are held together only by weak van der Waals forces; the shortest interlayer distance is a Te?Cl contact of 3.432(4) Å.  相似文献   

2.
A novel selective thiocyanate PVC membrane electrode based on bis-bebzoin-semitriethylenetetraamine binuclear copper(II) [Cu(II)2–BBSTA] as neutral carrier is reported, which displays an anti-Hofmeister selectivity sequence in following order: SCN > ClO4 > I >Sal >SO32− >NO3 > H2PO4 > Cl >NO2 > SO42−. The electrode exhibits Nernstian potential linear range to thiocyanate from 1.0 × 10−1 to 9.0 × 10−7 mol/l with a detection limit 7.0 × 10−7 mol/l and a slope of −57.0 mV/decade in pH 5.0 of phosphorate buffer solution at 25 °C. The response mechanism is discussed in view of the AC impedance technique and the UV spectroscopy technique. From comparison of potentiometric response characteristics between the binuclear metallic complex copper(II) [Cu(II)2–BBSTA] and mononuclear copper(II) metallic complex [Cu(II)–BBSDA], an enhanced response towards thiocyanate from the electrode based on binuclear metallic complex copper (II) [Cu(II)2–BBSTA] was observed. The electrode based on binuclear copper(II) compound was used to determine the thiocyanate content in waste water with satisfactory results.  相似文献   

3.
The new compound {[In(C6H14N2)2]2Sb4S8}Cl2 was prepared under solvothermal conditions reacting InCl3, Sb and S using 1,2-trans-diaminocyclohexane as solvent and structure directing molecule. The compound crystallizes in the monoclinic space group C2/c with a = 29.0259(12), b = 6.7896(2), c = 24.2023(12) Å, β = 99.524(4)°, V = 4703.9(3) Å3. The central structural motif is the thioantimonate(III) anion [Sb4S8]4? acting as a tetradentate ligand thus joining two symmetry related In3+ centered complexes. This binding mode was never observed before for the [Sb4S8]4? anion. The optical band gap was determined as 2.03 eV in agreement with the red color of the compound. The thermal decomposition was monitored with in-situ X-ray diffraction experiments. After the emission of the amine molecules an amorphous intermediate is formed followed by the crystallization of InSbS3 which is stable up to about 590 °C. On further heating, InSbS3 is destroyed and reflections of γ-In2S3 appear being contaminated with some elemental Sb. Temperature dependent in-situ X-ray powder diffractometry performed between 30 and 220 °C reveals an unusual reversible negative and positive thermal expansion. The decrease of the a-axis in the temperature range is about 0.74 Å and the increase of the c-axis ca. 0.54 Å. Interestingly, the b-axis exhibits also a thermal expansion, i.e., a biaxial positive and an uniaxial negative thermal expansion coexist which is very unusual. The relative negative expansion coefficients for the a-axis of ?194 × 10?6K?1 (30–120 °C) and ?82 × 10?6K?1 (120–220 °C) are in the region of so-called colossal thermal expansion.  相似文献   

4.
The [NpO2(DPPMO2)2Cl][NpO2Cl4] complex (where DPPMO2 = bis(diphenylphosphino)methanedioxide) contains the linear neptunyl group, {NpO2}2+, with two bidentate P=O donor ligands. Coordinating anion Cl? fills the fifth equatorial coordination site yielding a complex of general formula [NpO2(DPPMO2)2X]2[Y] (1) (where X = Cl? and Y = [NpO2Cl4]2?. Reaction between our newly prepared neptunium starting material [NpO2Cl2(thf)]n and phosphinimine ligand produced crystals of [Ph3PNH2]2[NpO2Cl4] (2). Compounds 1 and 2 have been structurally characterised.  相似文献   

5.
Group 4 [η13-tert-butyl(dimethylfluorenylsilyl)amido]dimethyl complexes [t-BuNSiMe2Flu]MMe2 (M = Ti, 1; Zr, 2; Hf, 3) were synthesized in a one-pot synthesis starting from the ligand, MeLi and MCl4 (M = Ti, Zr, Hf), respectively. The structures of these complexes were determined by X-ray crystallography and the results obtained revealed that the fluorenyl ligand coordinates to center metal in a η3-manner irrespective of center metal employed. Propylene polymerization was conducted at 0 or 20 °C in toluene by 13 combined with dried methylaluminoxane (MAO), which was prepared from the toluene solutions of MAO by removing free trialkylaluminiums, and HNMe2PhB(C6F5)4 in the presence of triisobutylaluminium. The 1–dried MAO system gave the polymer with syndiotactic triad (rr) of 63% at 0 °C, whereas 2 and 3 did not give any polymer in the same conditions. The 2–dried MAO system gave the polymer with the highest syndiotacticity (rr = 97%) at 20 °C, although the activity was low. The 3–dried MAO system did not give any polymer even at 20 °C. When HNMe2PhB(C6F5)4 was used in place of dried MAO at 20 °C, 1 gave almost atactic polymer, while 2 and 3 gave highly syndiotactic one (rr > 90%). These results indicate that the catalytic performance strongly depended on the center metal of the ansa-fluorenylamidodimethyl complexes as well as cocatalysts employed.  相似文献   

6.
Treatment of the amino acid derivative Bz-His-OMe with excess n-propyl bromide gave the corresponding histidinium salt [Bz-His(n-propyl)2-OMe+Br]. It features a melting point of 39 °C and may serve as a useful readily available optically active ionic liquid. Its subsequent treatment with silver oxide gave the corresponding l-histidine derived chiral N-heterocyclic carbene complex [“(carbene)2Ag · AgBr2”]. Transmetallation by treatment with Pd(CH3CN)2Cl2 or [Rh(cod)Cl]2 led to the formation of the respective chiral late metal imidazol-2-ylidene complexes [“(carbene)2PdCl2”] and [“(carbene)RhCl(cod)”], respectively. Four diastereomers of the square planar palladium system were observed. Due to the additional chirality center in the l-histidine-derived “Arduengo-carbene ligand” two diastereomers of the rhodium carbene complex were formed.  相似文献   

7.
A silicon carbide-based membrane was formed in the macropores of an α-alumina support tube by chemical vapor deposition of triisopropylsilane at 700–800°C with a forced cross-flow through the porous wall. The membrane permeated gases except H2O mainly by the Knudsen diffusion mechanism at permeation temperatures of 50–400°C. The H2/H2O selectivity was near or below unity because of the hydrophilic nature of the membrane. After a heat-treatment in Ar at 1000°C for 1 h, however, the membrane formed at a final evacuation pressure of 1 kPa exhibited a H2/H2O selectivity of 3–5, for a mixed feed of H2–H2O–HBr system, associated in a thermochemical water-splitting process. The H2 permeance was (5–6)×10−7 mol m−2 s−1 Pa−1 at 50–400°C. The membrane maintained the H2/H2O selectivity for more than 100 h in the H2–H2O–HBr mixture at 400°C.  相似文献   

8.
Dioxomolybdenum(VI) complexes of general formula [MoO2X2L2] (X = Cl, OSiPh3; L2 = 2-(1-butyl-3-pyrazolyl)pyridine, ethyl[3-(2-pyridyl)-1-pyrazolyl]acetate) were prepared and characterised by 1H NMR, IR and Raman spectroscopy. The assignment of the vibrational spectra was supported by ab initio calculations. A single crystal X-ray diffraction study of the complex [MoO2Cl2{ethyl[3-(2-pyridyl)-1-pyrazolyl]acetate}] showed that the compound is monomeric and crystallises in the tetragonal system with space group P41. The four complexes are active and selective catalysts for the liquid-phase epoxidation of olefins by tert-butylhydroperoxide. Selectivities to the corresponding epoxides were mostly 100% (for conversions of at least 34%) for the substrates cyclooctene, cyclododecene, 1-octene, trans-2-octene and (R)-(+)-limonene. For styrene epoxidation, the corresponding diol was also formed in significant quantities. The turnover frequencies for cyclooctene epoxidation at 55 °C were around 340 mol molMo−1 h−1 for the chloro complexes and 160 mol molMo−1 h−1 for the triphenylsiloxy complexes. The addition of co-solvents (1,2-dichloroethane or n-hexane) had a detrimental effect on catalytic activities. Kinetic studies for the two complexes bearing the ligand ethyl[3-(2-pyridyl)-1-pyrazolyl]acetate revealed an apparent first order dependence of the initial rate of cyclooctene conversion with respect to cyclooctene or oxidant concentration.  相似文献   

9.
Single crystals of a new phosphate AgCr2(PO4)(P2O7) have been prepared by the flux method and its structural and the infrared spectrum have been investigated. This compound crystallizes in the monoclinic system with the space group C2/c and the parameters are, a = 11.493 (3) Å, b = 8.486 (3) Å, c = 8.791 (2) Å, β = 114.56 (2)°, V = 779.8 (3) Å3and Z = 4. Its structure consists of CrO6 octahedra sharing corners with P2O7 units to form undulating chains extending infinitely along the [110] direction. These chains are connected by the phosphate tetrahedra giving rise to a 3D framework with six-sided tunnels parallel to the [101] direction, where the Ag+ ions are located. The infrared spectrum of this compound was interpreted on the basis of P2O74? and PO43? vibrations. The appearance of νsP–O–P in the spectrum suggests a bent P–O–P bridge for the P2O74? ions in the compound, which is in agreement with the X-ray data. The electrical measurements allow us to obtain the activation energy of (1.36 eV) and the conductivity measurements suggest that the charge carriers through the structure are the silver captions.  相似文献   

10.
Reactions of incomplete cubane-type clusters [(Cp°RuCl)2(μ-SH)(μ-SM′Cl2)] (M′ = Sb (2a), Bi; Cp° = η5-C5Me4Et) with 0.5 equiv of [PdCl2(cod)] (cod = 1,5-cyclooctadiene) afforded the corner-shared double cubane-type clusters [{(Cp°Ru)(Cp°RuCl)(μ-SM′Cl2)}23-S)2(μ-Cl)2Pd] (3a: M′ = Sb, 3b: M′ = Bi) in moderate yields, whereas treatment of 2a with 0.75 equiv of [PdCl2(cod)] gave the corner-shared triple cubane-type cluster [{(Cp°Ru)(Cp°RuCl)(μ-SSbCl2)(μ3-S)2(μ-Cl)2Pd}2(Cp°Ru)2] (4). Single-crystal X-ray analyses have disclosed the detailed structures of novel heptanuclear and decanuclear mixed-metal cores for 3a and 4, respectively.  相似文献   

11.
Redox stable K2NiF4 type layered perovskite SrLaFeO4  δ(SLFO4  δ) has been prepared and evaluated as anode for solid oxide fuel cell (SOFC). The SLFO4  δ shows linear thermal expansion behavior with TEC of 14.3 × 10 6 K 1. It also demonstrates excellent catalytic activity for various fuels. A scandia stabilized zirconia (ScSZ, 180 μm) electrolyte supported SOFC with the anode achieves maximum power densities (Pmax) of 0.93, 0.76, 0.63, and 0.46 Wcm 2 at 900–750 °C, respectively, in wet H2. Pmaxs of cells supported by 250 μm ScSZ reach 0.57, 0.60 and 0.50 Wcm 2 in H2, H2 + 50 ppm H2S and propane, respectively, at 800 °C. Moreover, the cells show stable power output during ~ 100 h operation at 800 °C under 0.7 V in various fuels. The Pmax at 800 °C in wet H2 even increases by ~ 11% in the subsequent two thermal cyclings, indicating that SLFO4  δ is a promising anode candidate for SOFC with good electro-catalytic activity, high stability and resistance to sulfur and coking.  相似文献   

12.
Picolyl, pyridine, and methyl functionalized N-heterocyclic carbene iridium complexes [Cp1Ir(C^N)Cl]Cl (4, C^N = 3-Methyl-1-picolyimidazol-2-ylidene), [Cp1Ir(C^N)Cl][Cp1IrCl3] (5), [Cp1Ir(C-N)Cl]Cl (6, C-N = 3-Methyl-1-pyridylimidazol-2-ylidene) and [Cp1Ir(L)Cl2] (7, L = 1,3-dimethylimidazol-2-ylidene) have been synthesized by transmetallation from Ag(I) carbene species, and characterized by 1H NMR, 13C NMR spectra and elemental analyses. The molecular structures of 5–7 have been confirmed by X-ray single-crystal analyses. The iridium carbene complexes 4 and 6 show moderate catalytic activities (3.03 × 105 g PNB (mol Ir)?1 h?1 and 1.70 × 106 g PNB (mol Ir)?1 h?1) for the addition polymerization of norbornene in the presence of methylaluminoxane (MAO) as co-catalyst. The produced polynorbornene have been characterized by IR, 1H NMR and 13C NMR spectra, showing it follows the vinyl-addition-type of polymerization.  相似文献   

13.
The interaction of [Nd(bpy)2Cl3·OH2], where bipy is 2,2′-bipyridine, with DNA has been studied by absorption, emission, and viscosity measurements. [Nd(bpy)2Cl3·OH2] showed absorption decreasing in charge transfer band with increasing of DNA. The binding constant, Kb has been determined by absorption measurement and found to be (1.5 ± 0.1) × 105 M?1. The fluorescent of [Nd(bpy)2Cl3·OH2] has been investigated in detail. The interaction was also studied by fluorescence quenching technique. The results of fluorescence titration revealed that DNA had the strong ability to quenching the intrinsic fluorescence of Nd(III) complex at 327 nm. The binding site number n, apparent binding constant Kb and the Stern–Volmer quenching constant KSV have been determined. Thermodynamic parameters have been calculated according to relevant fluorescent data and Van’t Hoff equation. Characterization of bonding mode has been studied. The results suggested that the major interaction mode between [Nd(bpy)2Cl3·OH2] and DNA was groove binding.  相似文献   

14.
The ansa-indene compound {1-Me2Si(3-C9H6Et)2} (1) was prepared by alkylation of the unsubstituted ansa-indene. This compound was converted, by reaction with nBuLi, to the dilithium compound [Li2{1-Me2Si(3-C9H5Et)2}] (2). ansa-Zirconocene [Zr{1-Me2Si(3-η5-C9H5Et)2}Cl2] (3) was prepared by the reaction of ZrCl4 with 2 in ether/toluene at −78 °C. The molecular structure of meso-3 was determined by single crystal X-ray diffraction studies. The ansa-zirconocene 3 exhibits a greater activity in ethylene polymerization than reference complexes such as [Zr{1-Me2Si(η5-C9H6)2}Cl2] and [Zr{1-C2H45-C9H5)2}Cl2] and, in addition, it maintained a reasonable level of activity after 12 h of contact with MAO solution. Furthermore, the different elementary steps in the activation process of ethylene polymerization for substituted complexes [Zr{1-Me2Si(3-η5-C9H5R)2}Cl2] (R = Et 3, Me 4, nPr 5 and nBu 6) by commercial methylaluminoxane (MAO) have been studied by UV–vis spectroscopy. Addition of MAO in large excess ([Al]/[Zr] = 2000) at −78 °C yields a previously unreported intermediate in the activation process of metallocenes; this intermediate has an absorption band centered at λ = 639 nm. We report here the influence of the type of catalyst, ring substitution, type of cocatalyst and addition of THF on the activation process of these metallocenes.  相似文献   

15.
The electrochemical measurements were carried out by using thermophilic cytochrome P450 CYP119A2 (P450st) modified with poly(ethylene oxide) (PEO) in PEO200 as an electrochemical solvent. The PEO modified P450st gave clear reduction–oxidation peaks by cyclic voltammetry in oxygen-free PEO200 up to 120 °C. The midpoint potential measured for the P450st was −120 mV vs. [Fe(CN)6]4−/[Fe(CN)6]3− at 120 °C. The peak separation, ΔE, was 16 mV at 100 mV/s. The estimated electron transfer rate of PEO-P450st at 120 °C was 35.1 s−1. The faster electron transfer reaction was achieved at higher temperatures. The electrochemical reduction of dioxygen was observed at 115 °C with the PEO-modified P450st system.  相似文献   

16.
2-Bromopyridine reacts with elemental phosphorus (red or white) in a superbasic KOH/DMSO(H2O) suspension at 100 °C (for red phosphorus) and 75 °C (for white phosphorus) over 3 h to afford tris(2-pyridyl)phosphine in a 62% yield (from red phosphorus) and a 50% yield (from white phosphorus). Under microwave assistance, the reaction with red phosphorus takes just 20 min to produce tris(2-pyridyl)phosphine in 53% yield. A hitherto unknown complex, [Pd(PPy3)2Cl2]·CH2Cl2, synthesized from tris(2-pyridyl)phosphine and PdCl2, has the cis-configuration; this is unusual for bis(phosphino)palladium dichloride complexes.  相似文献   

17.
《Solid State Sciences》2007,9(9):777-784
Petroleum coke and those heat-treated at 1860 °C, 2100 °C, 2300 °C 2600 °C and 2800 °C (abbreviated as PC, PC1860, PC2100, PC2300, PC2600 and PC2800) were fluorinated by elemental fluorine of 3 × 104 Pa at 200 °C and 300 °C for 2 min. Natural graphite powder samples with average particle sizes of 5 μm, 10 μm and 15 μm (abbreviated as NG5μm, NG10μm and NG15μm) were also fluorinated by ClF3 of 3 × 104 Pa at 200 °C and 300 °C for 2 min. Transmission electron microscopic (TEM) observation revealed that closed edge of PC2800 was destroyed and opened by surface fluorination, which increased the first coulombic efficiencies of PC2300, PC2600 and PC2800 by 12.1–18.2% at 60 mA/g and by 13.3–25.8% at 150 mA/g in 1 mol/dm3 LiClO4–ethylene carbonate (EC)/diethyl carbonate (DEC) (1:1 in volume). Light fluorination of NG10μm and NG15μm increased the first coulombic efficiencies by 22.1–28.4% at 150 mA/g in 1 mol/dm3 LiClO4–EC/DEC/PC (PC: propylene carbonate, 1:1:1 in volume).  相似文献   

18.
Electrochemical lithium intercalation within graphite from 1 mol dm 3 solution of LiClO4 in propylene carbonate (PC) was investigated at 25 and − 15 °C. Lithium ions were intercalated into and de-intercalated from graphite reversibly at − 15 °C despite the use of pure PC as the solvent. However, ceaseless solvent decomposition and intense exfoliation of graphene layers occurred at 25 °C. The results of the Raman spectroscopic analysis indicated that the interaction between PC molecules and lithium ions became weaker at − 15 °C by chemical exchange effects, which suggested that the thermodynamic stability of the solvated lithium ions was an important factor that determined the formation of a solid electrolyte interface (SEI) in PC-based solutions. Charge–discharge analysis revealed that the nature of the SEI formed at − 15 °C in 1 mol dm 3 of LiClO4 in PC was significantly different from that formed at 25 °C in 1 mol dm 3 of LiClO4 in PC containing vinylene carbonate, 3.27 mol kg 1 of LiClO4 in PC, and 1 mol dm 3 of LiClO4 in ethylene carbonate.  相似文献   

19.
Preliminary tests of the chlorination of two iron oxides (wüstite and hematite) in various chlorinating gas mixtures were performed by thermogravimetric analysis (TGA) under non-isothermal conditions. Wüstite started to react with chlorine from about 200 °C generating ferric chloride and hematite as the final reaction products. The presence of a reducing and oxidizing agent in the chlorinating gas mixtures influenced the chlorination reactions of both iron oxides, during non-isothermal treatment, only at temperatures higher than 500 °C.The chlorination kinetics of hematite with Cl2 have been studied in details between 600 and 1025 °C under isothermal chlorination. The values of the apparent activation energy (Ea) were about 180 and 75 kJ/mol in the temperature ranges of 600–875 and 875–1025 °C, respectively. The apparent reaction order with respect to Cl2 was found to be 0.67 at 750 °C. Mathematical model fitting of the kinetics data was carried out to determine the most probable reaction mechanisms.  相似文献   

20.
The coupling of propiolic acid with aryl iodides afforded the aryl alkynyl carboxylic acids and aryl alkynes in generally good yields. Aryl alkynyl carboxylic acids were obtained when the reaction was performed in the presence of Pd(PPh3)2Cl2 (2.5 mol %), dppb (5.0 mol %) and DBU (5 equiv) at 50 °C. For the synthesis of the terminal aryl alkynes, the reaction was conducted in the presence of Pd(PPh3)2Cl2 (2.5 mol %), dppb (5.0 mol %), DBU (5.0 equiv), and Cu(acac)2 (10 mol %) at 25 °C for 5 h, and further reacted at 60 °C for 6 h.  相似文献   

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